PT97342B - PROCESS FOR THE MANUFACTURE OF CHEMICAL RESISTANT LIQUID CRYSTALS AND CUTTING AND DISPLAY DEVICES - Google Patents

Description

Process for manufacturing shock resistant liquid crystal display and switching devices

DESCRIPTION

Visualization and connection devices containing ferroelectric liquid crystals (FLC light valves) are known, for example, by means of the European patent EP-B 0 032 362 (= US-A 4 367 924). Liquid crystal valves are devices that, for example, by means of an electrical connection, change their optical transmission properties so that the light that passes through them (and eventually reflected back) is modulated by intensity. Examples are known indicators for watches and pocket calculators or liquid crystal displays used in the field of OA (office automation) or TV (television). However, among them there are also optical shutters, the so-called light shutters (light shutters) as used, for example, in photocopying machines, printers, welding glasses, polarized light glasses for three-dimensional observation, etc. Also called spatial light modulators (spatial light modulators) count in the field of use of liquid crystal light valves (see Liquid Crystal Device Handbook, Nikkan Kogyo Shimbun, Tokyo, 1989;

ISBN 4-526-02590-9C 3054 and the works cited there).

The connection devices and the electro-optical visualizers are constructed in such a way that the FLC layer is enclosed on both sides by layers that are usually found in this sequence from the FLC layer, at least one orientation layer, electrodes and a limiting disc (for example glass). In addition, they contain a polarizer whenever they work in the guest-host mode or in the reflection mode, or two polarizers if the birefringence mode is used as the mode. The connecting and display elements may also contain other auxiliary layers, for example, diffusion blocking layers or insulation layers.

These orientation layers cause, together with a sufficiently small chosen distance from the limiting discs, the FLC molecules of the FLC mixture assume a configuration in which the molecules are with their longitudinal axes parallel to each other and the perpendicular emetic planes. or inclined with respect to the orientation layer. In this arrangement, the molecules have, as is known, two orientations of equal value, between which they can be connected by applying pulses from an electric field, that is, the FLC visualizers can be bistably connected. The connection times are, on the contrary, proportional to the spontaneous polarization of the FLC mixture and are of the order of magnitude of microseconds.

The main advantage of the FLC viewers over the LC viewers that are still in industrial use is considered the multiplex behavior that can be achieved, that is, the maximum number of lines controllable by the sequential process (multiplex process) that, in the case of the FLC viewer is prati3

unlimited, unlike traditional LC viewers. This electrical control is essentially based on the pulse addressing mentioned above and described, for example in SID 85 DIGEST page 131 (1985).

A known problem with FLC viewers is the sensitivity of orientation of liquid crystal materials in the liquid crystal layer in relation to deformations caused mechanically or thermally. See, for example, ST Lagerwall et al., Ferroelectrics 94, 3 - 65 , (1989) / 7 - in most cases referred to through the expression shock instability.

The reason for this fact, which constitutes a non-relevant problem for nematic visualizers, is based on an inherent property of ferroelectric liquid crystals - the existence of the smectic layer structure. The high flow viscosity prevents spontaneous elimination of disturbances caused by external forces of the structure in appropriate layers. In general, the initial geometry can only be established by heating the viewer in order to move to the nematic or isotropic phase which generally requires high temperatures and is technically expensive.

As the origin of the shock instability is based on the intrinsic properties described before the smectic liquid crystals, this problem has been considered until today as especially serious.

The attempts made today to solve the shock problem consist of avoiding the possible deformations for which a stable structure of the Z * viewer is built, for example by using structured photo spacers

(Leti, France) ^ or the viewer is placed on an elastic structure (Canon, Japan). In this case, the high costs of manufacturing such a device and the fact that, however, the effects of intense forces lead to the destruction of the smectic layers are inconvenient.

The applicant has now surprisingly discovered that, using connection and visualization devices with a mixture of FLCs containing coronands or cryptos, it is possible to give the FLC material a geometry of a bookshelf or quasi-bookshelf (quasi- bookshelf) / f ^ve j ^{is the} Dubal et al., Proc. 6th Intl, Symp, on Electrets, Oxford, England, 1988; Y. Sato et al., Jap. J. Appl. Phys. 28, L 483 (1989). This structure is more resistant to deformation than the so-called Chevron geometry with the smectic layer at an angle.

The invention therefore relates to a process for the manufacture of shock-resistant liquid crystal display and connection devices, characterized in that they have at least one orientation layer, at least one polarizer is provided and is filled the empty space between the two support plates with a liquid crystal material, in which the liquid crystal material uses a mixture of ferroelectric liquid crystals that contain at least one base component of liquid crystals and still at least one crypting or a coronary and, before the start-up, a periodic continuous electrical voltage is applied to the electrodes of the connecting and display device for a time sufficient for the liquid crystal layer to assume a bookshelf orientation.

or almost bookshelf (quasi-bookshelf).

As cryptos or coronands, the following compounds of general formulas (X) or (II) are preferably used:

ÇH ₂ - (- CH ₂ -Z-CH ₂ ) _m -ÇH ₂

CH .- (- CH.-Z-CEI.) -CH.

2 2 n 2 in which the symbol -Z- represents an oxygen atom (-0-) or a sulfur atom (-S-) and the symbols men represent numbers greater than 0, such that the sum m + n = 2 to 6, the symbols -Xg- and ^s ^ ° Í9 ^ua -i ^{s or} different and represent

or the two symbols -Xg- θ -Xg ^- together represent> N-CHg (-CHg-Z-CHg) g-CHg-N ^, or ^> N-CO (-CH ₂ -Z-CH ₂ ) g-CO-Ní where the symbol -R- represents an alkyl or alkanoyl radical having one to fifteen carbon atoms, phenyl, benzyl or benzoyl and the symbol representa represents number 1 or number 2;

Rn

N- (CH ₂ ) _p <f ^H 2> s

N 1 ^R 4

Wr

R, r

N (CH.)

I

N

I

R, (II) in which the symbols -R ^ z -R ₂ , ^-R 3 ^and “ ^R 4 'independently of each other, each represent a hydrogen atom or a group of one of the formulas

-The ^CH 3-. / o ch ₃ , -ch ₂

COOH

and the symbols p, q, res, independently of each other, each represent an integer between 2 and 4, where the sum p + q + r + s = 8al6.

Preferably, the compounds of general formula (I) are also used, in which the symbol Z represents an oxygen atom, the symbols men represent numbers greater than 0 and in such a way that the sum m + n = 2 to 4 , the symbols -X ^ - θ “ ^X 2 ~ ^s ^ ° -'- 'J ¹¹³ --'- ^{3 or} different and represent the substituents of formulas

-NR-0-

0-0

or the symbols -X ^ - and -X ₂ ~, together, represent

0 \ N-CH ₂ (-CH ₂ -O-CH ₂ ) ₁ -ΟΗ ₂ -Ν <ζ '

ζ.

wherein the symbol -R- represents an alkyl or alkanoyl group having one to fifteen carbon atoms, phenyl, benzyl or benzoyl and the symbol X represents the numbers 1 or 2.

Of the compounds of general formula (II), preferably those are used where the symbols -R ^, -R ₂ ^and “^ 3 represent hydrogen atoms and the symbol * R ^ represents a hydrogen atom or one of the radicals of formulas, -CH ^; or -CH

COOH.

The FLC mixture preferably contains between 0.01 and 10 mole% of the compounds of the general formulas (I) and (II).

Preferably, the mixture also contains several different compounds of general formulas (I) and / or (II), although, however, the total quality is preferably between 0.01 and 10 mole%.

To obtain a book shelf geometry (bookshelf) or quasi book shelf (quasi bookshelf), the ferroelectric phase is applied to the electrode, preferably using a periodic square wave voltage with a frequency between 1 and 1 000 Hz and a field strength of 0.5 to 50 V / µm over a period of time between 0.1 second and 10 minutes. In this case, a higher frequency and a lower field intensity are chosen the greater the spontaneous polarization and the higher the temperature at which the treatment with the electric field is carried out.

Particularly preferred is an embodiment of the present invention in which the electrodes are subjected to a periodic square wave voltage with a field strength of 5 to 20 V / min and a frequency of 2 to 50 Hz for a period of time between a second and two minutes.

It is also especially preferred that the treatment with the electric field is carried out with a periodic voltage of square wave at the working temperature value or a tight temperature range (+ 10 ° C) in relation to the preferred working temperature value.

As a special advantage of the process according to the present invention, it is pointed out that it is possible to return a viewer by a shock with the use of the aforementioned FLC mixes back to the initial state in a simple way and also in normal operation by the users at random or according to a routine - namely by treatment for a short time with an appropriate electric field.

According to a special embodiment of the present invention, the indicating and display device contains an additional constructive element that enables or facilitates the application of the continuous periodic square wave voltage in routine operation.

The invention therefore also relates to a process of regeneration of a shock-affected liquid crystal display and connection device containing two support plates, at least one orientation layer, a glued frame, electrodes, at least least one polarizer and a liquid crystal material _t in which the liquid crystal layer have originally (i.e., before being affected by shock) an orientation swath prate books (bookshelf ") or quasi - bookshelf

(quasi bookshelf) that a layer of liquid crystals consisting of a mixture of ferroelectric liquid crystals consisting of at least one base component of liquid crystals and at least one coronary or crypting element is used and applies to the electrode of the connection device or visualization affected by the shock a continuous periodic voltage.

Preferably, in the connector and display device, the special FLC mixtures mentioned above are used. The voltage applied to the electrodes of the visualizer affected by shock or freezing is preferably a square wave voltage and preferably has a frequency between 1 and 1 000 Hz, in particular between 2 and 50 Hz and an intensity of electric field between 0.5 and 50, in particular between 5 and 20 V / micrometer.

For regeneration, tension is preferably applied for a period of time from 0.1 to 10 minutes, in particular for 1 second to 2 minutes. Applying the voltage for too long is less advantageous for economic reasons.

Another problem with the use of ferroelectric liquid crystals in FLC displays is that the minimum temperature at which these displays can be kept too high, that is, low temperatures (as, for example, can be seen in airplanes) originate also texture disturbances. If the liquid crystal material in the viewer crystallizes, then the viewer loses its good bonding properties after melting again. Only a heating until the cholesteric or isotropic phase is reached and the subsequent cooling to the working temperature allows to obtain the behavior

original connection of the FLC viewer.

In this regard, the process according to the present invention is especially advantageous as mentioned above. It has been found that FLC viewers that have frozen and liquefied again, which are filled with the FLC mixtures described above, can be brought back to good initial bonding status (such as high contrast) by treatment for a short time of time with a continuous periodic electric field.

The FLC light valves that form the basis of the process according to the present invention contain a mixture of ferroelectric liquid crystals (FLC mixture) that contains at least one coronary and / or one crypting.

As FLC light valves used in the process according to the present invention, connection devices that are controlled by a multiplex process are preferred. Especially preferred are liquid crystal cells that work according to the SSFLC (Surface stabilized ferroelectric liquid crystal) technique (i.e., superficially stabilized ferroelectric liquid crystals) in which the layer thickness (ie the distance between the limiting discs) ) is between 1 and 20 micrometers. A layer thickness between 1 and 10 micrometers and, in particular, between 1.2 and 3 micrometers is particularly preferred.

In the working temperature range, the mixture of * -

FLC preferably has an S _c phase and the phase sequence of the mixture is IN * -S * -S * or IN * -S *.

Ac c

The invention is clarified in more detail by means of the following Examples 1 to 4.

EXAMPLES

Example 1

A liquid crystal base mixture is prepared from the following eight components (amounts expressed as a mole percentage):

13.39

4.49

14.78

8.14 ^H 17 ^C 8 ^-0

° - ^C 6 ^H 13 ^H 17 ^C 8 ° '

1W

N

° “ ^C 8 ^H 17 ^H 17 ^C 8 ⁰

° -c ₄ h ₉ .N ^H 17 ^C 8 ~ °

° - ^C 10 ^H 21

8.16

25

0 ^C 5 ^H 11

12.00

20.00

The mixture has the following sequence of phases:

S 71 S ^ 78 N 93 I. c A

As chiral doping substances, the following compounds are used:

Dl doping compound:

(S)

D2 doping compound:

'8 17' 8 17

cis

Doping compound D3 ^C 8 ^H 17

NO-CH: C, H _r * * '- 4 ^Xi 9 (S) (S) trans

A comparison mixture (V) (for the following tests)

has the following composition (in percent in moles): (V) - base mixture 87.67 - Dl doping compound 4.53 - D2 doping compound 2.70 - D3 doping compound 5.10 k k k and has the following sequence of S phases _c 61 69 N 85 I, with a spontaneous polarization equal -2 at 30 nc.cm, at 25 ° C. As coronating (C) or encrypting (K), the two are used

following compounds with the following formulas:

2'2

CH ₂ CH ₂ -O (-CH ₂ ) ₂ “O“ CH ₂ CH

N- (CH ₂ ) ₂ -O - (- CH ₂ ) ₂ -O - (- CH ₂ ) ₂ -N

o (-ch ₂ > ₂ -ο - (- ch ₂ ) ₂ -ο (C)

CH ₂ CH ₂ -O (-ch ₂ ) ₂ -O-CH ₂ CH ₂ (K)

As an FLC mixture that serves as the basis for the process according to the present invention, the mixture X with the following composition (in mole percent) is prepared as an example:

(X)

- 98.0 comparison mixture (V)

1.5 coronary (C)

0.5 encrypting (K).

As a second mixture of FLC containing a cryptoid and / or a coronary, the Y mixture is prepared. It has the following composition (in mole percent):

(Y)

17 ^C 8 ° -C ₆ ^h i ₃

14.6

^H 17 ^C 8 “°

9.7

13.1

9.1

^h 17 ^C 8 ~ °

4.2

17 ^H 17 ^C 8 °

oc ₄ h ₉

21

-0- <

'5 11 ^H 17 ^C 8

O-CH -Z _ \ _ C ₄ H (S) (S) ^H 17 ^c 8-O

O-CH

IN

2 <Ο

7.7

14.4

5.7

3.4. KT ^h 17 ^C 8 “O

O / LY o-co-i- £ -C _o H * * ^ 3 7 (R) (R)

6.5

- coronary (C)

- crypting (K)

1.5

0.5 .o

At a temperature of 25 C, it has a spontaneous polarization -2 equal to 31 nC.cm and the following sequence of phases:

X -3 S 64 72 N 83 L c A

Example 2

The method described before the texture change caused by the electric field is used with the mixture of Example 1 that serves as the basis for the process according to the present invention and with the comparison mixture V.

To a LC cell that can be obtained commercially with a thickness of 2 micrometers (manufacturer: EHC & Co., Ltd., Tokyo, Japan) rubbed in parallel (PIX 1400 from Hitachi Ltd., Tokyo, Japan) as a guiding layer , a square wave periodic voltage of 25 volts amplitude and a frequency of 10 Hz is applied at room temperature.

In Figure la and Figure lb, photomicrographs (125-fold magnification) of the resulting quasi bookshelf geometry (quasi bookshelf) are shown respectively for mixture X and comparison mixture V. In Figure lb, the texture is clear macroscopically inhomogeneous and in Figure la, the microscopic texture characteristically with bands is recognized, although it is macroscopically uniform. The connection with bipolar pulses (as usually happens in multiplex systems) gives rise to the optical transmission curves shown in Figures 2a and 2b, respectively for the FLC X mixture and for the comparison mixture. Optical transmission was measured for which the cells were placed, as is usual in the SSFLC technique, between two crossed polarizers. A high contrast (of about 30: 1) is obtained in the case of the X mixture (Figure 2a) and, on the contrary, a small contrast (equal to about 3: 1) in the case of the comparison mixture (Figure 2b) .

Example 3

To demonstrate the special properties of the FLC mixtures * * used in the process according to the present invention in relation to the possibility of regenerating a crystallized and fused liquid crystal mixture (connector damaged by temperature) by treatment with an electric field, so that the original behavior is again verified (high optic contrast), they are filled with the mixtures X and Y described in Example 1 and the comparison mixture V respectively liquid crystal cells that have a distance with the thickness of 2 micrometers and that they are provided with a layer of polyimide (as an orientation layer) with the thickness of nanometers. The cells are subjected to a treatment for three minutes with a square wave continuous voltage with a frequency of 10 Hz and an amplitude of 20 V.

By subsequent application of bipolar connection pulses (for example, with a field strength of 8 V / yim ^X and a pulse duration of 0.5 msec), the director moves (orientation of the molecules' axes) according to the indication of the bipolar impulse used for the two stable positions that tend to the connection angle 2 © θ ^. The cell is thermostabilized at a temperature of 25 ° C and placed under a polarizing microscope so that one of the two states has the smallest possible transmission and the other state has a high transmission. The values indicated in Table 1 of the optical transmission refer to the maximum transmission of light by the FLC cells with a parallel position of the polarizers. In Table 1, the values given for the FLC mixtures referred to in Example 1 with coronands or cryptos show the high quality of orientation in the darkened state (transmission

small, T ^), as well as the advantageously large angle (2 θθ ^) that gives rise to a high transmission in the illuminated state (maximum transmission, T ^) (see Table 1, a).

Both cells, after heat shock treatment (crystallization and subsequent fusion) show worse transmission and, consequently, worse contrast (see Table 1, b).

The comparison of the values of the determinations in case a) and in case b) shows that the contrast decreases from values between 23 and 32%. A decisive advantage of FLC mixtures containing cryptos or coronands is that it is possible to increase the contrast in the cells by re-treating them with an electric field (as described above). Comparing the values of measurements c) with d), it can be concluded that the contrast can increase between 24 and 29% through the treatment with the field and, therefore, can reach the contrast of the original cell (before the crystallization of the FLC).

A shock-damaged connection and visualization device that contains a mixture of FLC with cryptocurrent and / or coronary can thus be regenerated by applying a simple continuous alternating voltage so that the quality of the initial device is obtained again.

I

Η

I ω

Φ

ΙΟ θ ’

Φ>

> 4 φ

ω φ

4-1 ω ό Φ Ε4

-Ρ X! 0 £ 4 υ υ

φ Ό 0 ΙΦ 0 ο » γ-4 φ Φ ο Ο> Η

Η «3

Φ

Ρ Φ 0 Η ω ο ω Η φιφ CU ο ω Η

οι

Ό

Φ

ΟΙ

Ο I — I ο,

£ 0 I φ ω 0 4-1 '0 ό ω Φ Λ Φ Οι £ ω Φ Φ Ό Φ 2 Φ 0 íd Ό Φ ω 0 ω 2 0 Φ 0 ΗΙφ -Η ψί 0 4-1 ζ—> Φ ω Φ • Η Φ 0 X 0 0 rj QJ 44 44 υ ijm-i Ο 44 4-1 • Η ω γ4 Ή ΙΦ Ο ρ Φ Φ τη ιφ Ο 4-1 τ3 υ Ο, 3 γΗ ΡΙ 0 Φ ιΦ 0 .Φ φ £. ιφ 4-ΐ ϋ, Ιφ h χ ι-4 0 σ- ο 0 Φ Φ Φ φ φ Φ ιφ Οι Ό • Η <0 Ν Ό!> £ 0 44 • Η φ Φ ω 0. 0 ω η Φ frog υ Φ £ Φ Φ 44 φ Η ι — ι Φ φ ι — 1 4-1 0 ι — 1 Γβ ο

Φ ϋ Ρ ο Ο-Ρ ι—) Ο γ-) -Η CO r-H £ ιφ 0 Φ ιφ 44 -Η Ιφ ’0 ο υ g υ ο ε υ δ ο

- + - ^ 00 Ό m

σι ω Η χ χ ο ο Ο θ ' Γ ' Γ-

04 40 04

χ. χ χ

Η ι — 1 Η ο ο ο ιη ιη ιη

0 1 τη Ο φ ιθ 44 Ο Φ ω Φ Φ Ό φ Φ Ό Ο ω 0 Φ Φ · Γ4ΙΦ +> 44 ^ χ φ ω Φ X Φ Φ 44 0 03 * 4-4 -μ Ο ω Η Η Φ φ U 44 Ό ο ιΦ 44 Φ Φ 0 Ο υ 44 £,! Φ ιφ 0 Ο Φ Η Φ Φ Φ Ό φ • Η Ό Ν 44 γ4 ω 0 0 ω η Φ Φ ο Φ Φ 44 1—4 £ Φ Γ-) 44 φ 0 Φ 44 Φ ω 44 ι — 1 U 0 ι-4 · Η ω ιφ Φ ιφ 44 Η υ 0 £ U 0 £

υ> 2 £ Φ * Ϊ4 0 Μ χ υ Φ! § 0 Ό Ο »44 0 (d Φ ο τη ν Φ · Η Φη £ 44 r-f (d Φ 44 Φ 44 44 0 1—) -W φιφ ' ^φ d 44 1-4 U Ο 44 φ

ιο sr ιη <34 r · ο

I — I θ 'Γ' χ χ χ

Ο Ο θ 'Γ I <34 40 θ' θ '<31 40

XXX ο ο ο

40 40

Μ ·

Ο Ο ο | —1 r — 1 Γ — 1 03 03 ro 00 Γ0 ΓΟ * χ * » ο » γΗ Η 1—1 I — 1 Η γΗ

Example 4 present Example demonstrates, on the one hand, the greater shock resistance of quasi bookshelf geometry in relation to mechanical deformation compared to Chevron geometry and, on the other hand, the possibility of dealing with new through treatment with electric field a cell of almost book shelf geometry (quasi bookshelf) impaired by mechanical actions.

In order to carry out the test comparing the behavior of the connection and visualization devices with respect to mechanical deformation, the test cells, which can be obtained commercially, represented in Figures 6a and 6b (from the manufacturer Ε. HC) with the X mixture according to the present invention. The cell has only spacers (G) in the glued frame (G) and is easily deformable by pressure applied to the middle part of the cell.

Figure 6a represents the cell in side view. Figure 6b shows the complete cell (22 x 25 millimeters) in plan, in which the pressure application point (I) and the connection field (H) (4x4 millimeters) are specially marked.

The cell (Ε), as shown in Figure 7, is placed on a scale (A) and is subjected to joint pressure by means of a screw device (B) fixed to a frame (D) with a static sleeve (C) a from the top with a 1.5 mm diameter die (F) for ten seconds. The force of the stamp is regulated in a well-defined manner with the aid of the scale indicator and is varied. Before and after the application of force, the texture and binding behavior of the exactly placed cell are microscopically determined

below the pressure point (diameter = 1.5 mm) (I).

Figure 4b represents the texture photomicrograph in the case of Chevron geometry with a magnification of one hundred and twenty-five times without mechanical load (bl) and after loads of various intensities (b2) to (b5) (bl = 0 gram; b2 = 200 grams; b3 = 300 grams; b4 = 400 grams; b5 = 500 grams).

In this case, a change in texture is clearly recognized after a load of 400 grams. This is also clearly demonstrated by the decrease in contrast when bipolar impulses are connected (see Frame 2).

It is only possible to restore the original texture and obtain the original contrast by heating to the cholesteric or isotropic phase, that is, using high temperatures

If, however, on the contrary, the device contains a mixture containing coronands and / or cryptos, by treatment with an electric field as mentioned above, a quasi bookshelf geometry is obtained and then the load test mechanics, as shown in the photographs taken at a magnification of one hundred and twenty-five times (Figure 4a), demonstrates that, in this case, only from a load of 600 grams essential changes in texture are verified (al = 0 gram; a2 = 400 grams; a3 = 500 grams; a4 = 600 grams; a5 = 1,000 grams). This is also reflected in the contrast values mentioned in Table 3.

Example 5

The 1000 gram loaded cell of Example 4 is subjected // see Figure 4 (a5) J7 to a treatment with an r 21 field

electric field £ as has been used before to transform Chevron geometry into quasi bookshelf geometry (quasi bookshelf) J7. Surprisingly, it is also found in this case that a heavily damaged cell / see Figure 5 (a), which corresponds to Figure 4 (a5) can be regenerated completely again (Figure 5 (b) £.

This fact is also demonstrated by determining the contrast which for damaged cells Figure 5 (a) J gives a contrast value of 8: 1 and for the regenerated cell a contrast of 75: 1.

The comparison with the contrast of the charge application cell (Table 3) shows that the cell can also be completely regenerated with respect to its optical characteristics by means of treatment with the electric field.

TABLE 2

Contrast of a connection and visualization device after being loaded with a certain intensity (in Chevron geometry)

Load (g) Contrast 0 13.4 100 13.3 200 13.7 300 13.7 400 10.5 500 10.0 600 9.8 700 7.2

TABLE 3

Contrast of a connection and visualization device after being subjected to a load with a certain intensity / 7 in the geometry of

almost book shelf (nearly bookshelf ^ Load (g) Contrast 0 68.0 200 67.7 300 67.7 400 71.1 500 73.0 600 11.1 700 11.0 800 9.4 1,000 8.0

Claims (9)

1.- Process for the manufacture of a shock resistant liquid crystal display and switching device, according to which two support plates connected with each other are used, of which at least one has an orientation layer, it is equipped with electrodes and at least one polisher and in the intermediate space between the two support plates a liquid crystal material is added, characterized by the fact that, as liquid crystal material, a mixture of ferroelectric liquid crystals is used which contains at least a base component for liquid crystals plus at least one crypt or one coronary and, before commissioning, apply to the electrodes of the switching and visualization device -ηtion in the ferroelectric phase a continuous periodic electrical voltage for the time sufficient for the liquid crystal layer to assume the orientation of the bookshelf (quasibookshelf) or bookshelf. 2. A process according to claim 1, characterized in that the mixture of free crystals employed contains at least one cryptoid or one coronary of one of the following general formulas (I) and (II) CH ₀ - (- CH _O -Z-CH _O ) -CH ₀ j δ ί ί mjz χ _η x, (I) I ¹ I ² CH ₂ - (- CH ₂ -Z-CH ₂ ) _n -ÒH ₂ in which each of the symbols -Z- represents an oxygen atom -0- or sulfur atom -S- and the men symbols represent integers greater than that zero and such that m + n = 2 to 6, the symbols -X ^ - ® " ^X 2" ^are ^ U ^ua; * - ^{S or} different and have one of these meanings or ₂ and X ~ ^together have one of the following meanings "· \ / \ / N-CH ₂ (-CH ₂ -Z-CH ₂ ) ^ - CH ₂ -N <^, N-CO (-CH ₂ -Z-CH ₂ ) £ -CO-N <L where R is an alkyl or alkanoyl radical with 1 to 15 carbon, phenyl, benzyl or benzoyl atoms and £ is integer 1 or 2; R-ι R ₉ l ¹ I ² N - (CH ₀ ) - N t ² p 1 (II) (ch ₂ ) _s < ^c H ₂ ) _g N - (CH) - N I 2 r I R, R. in which the symbols R _lz r ₂ , r ₃ and R ₄ , independently of each other, each represent one of the groups of other formulas, each representing an integer between 2 and 4, where p + q + r + s = 8 to 16, -26 and a periodic square wave voltage with a frequency of 1 to 1000 Hz and an electric field strength of 0.5 to 50 V / must be applied to the electrodes for a period of time between 0.1 seconds and 10 seconds minutes. Process according to Claim 2, characterized in that the liquid crystal mixture used contains a compound of general formula (I), in which the symbol Z represents an oxygen atom, the symbols men represent numbers greater than zero , and the sum m + n = 2 to 4, the symbols X ^ - and ^"X 2" ° ^ ^s i9 ^{HAT or} different and represent one of the following groups or -X ^ symbols - and -X ₂ ~ together represent a grouping of general formula J? N-ch ₂ (-ch ₂ -o-ch ₂ ) £ -ch ₂ -nZ in which R represents an alkyl or alkanoyl group having 1 to 15 carbon, phenyl, benzyl or benzoyl atoms and the symbol £, represents the number 1 or 2. 4. The process according to claim 2, characterized in that the liquid crystal mixture used contains a compound of general formula (II), in which the symbols R ^, Rg and Rg are the same and each represent , an act of hydrogen and the symbol R ^ represents a substituent of one of the formulas -CHg or -CHg COOH due to the fact that a periodic square wave voltage is applied to the electrodes with an intensity of the electric field between 5 and 20 V / jxa and a frequency of 2 to 50 Hz over a period of time between 1 second and 2 minutes. 6.- Process for the regeneration of a liquid crystal display and switching device damaged by a shock, comprising two support plates, at least one orientation layer, a glued frame, electrodes, at least a polarizer and liquid crystal material and was originally in a bookshelf or quasibookshelf orientation in the free crystal layer, characterized by the use of a liquid crystal layer of a mixture of ferroelectric liquid crystals consisting of at least one base component of free crystals plus at least one corona or crypting and to apply to the electrodes of the damaged switching and visualization device a square wave voltage ' periodic, continuous. 7. Process according to claim 6, characterized in that a periodic square wave voltage with a frequency between 1 and 1000 Hz and a electric field strength from 0.5 to 50 V / um · 8. A method according to claim 6, characterized in that the electrodes are subjected to a periodic square wave voltage with a frequency between 2 and 50 Hz and an electric field strength of 5 to 20 V / jint over a period time from 1 second to 2 minutes. 9. A method according to claim 6, characterized in that the connection and display device comprises an additional element which makes it possible to apply the continuous periodic square wave voltage in the operation of rotir® Ayeníe Oficial do Property Industrio! f «q. ia [Λ] ΊιΓα'.3α